Items can be vital to surviving battles in Paper Mario: The Thousand-Year Door, so it's in a player's best interest to be prepared for any situation by having a good stock on hand. However, many people can feel stifled by the amount of inventory space given to them, despite one of the newly added features to the remake being expanding the base number from 10 items to 15 items. Luckily, if players are seeking to stretch that number even further, there is an upgrade waiting for them deep beneath the sewers of Rogueport.